John McCusker / The Times-PicayuneThe Discoverer Enterprise is pictured last summer at the site of the Deepwater Horizon explosion. The last section of the Gulf, immediately surrounding the accident site, was reopened to fishing Tuesday.

Twelve sections of the Gulf were closed since July 22 due to the massive oil spill. All are now reopened.

This reopening was announced after consultation with the U.S. Food and Drug Administration, according to a news release.

NOAA sampled seafood in the area between November 11 and November 14, 2010, March 12 and March 16, 2011, and March 28 and April 1, 2011, for potentially affected finfish, including tuna, swordfish, and escolar.

Sensory tests of 86 finfish samples found no detectable oil or dispersant odors or flavors. Chemical tests of 112 finfish samples found that oil-related compounds and dispersants were well below the levels of concern. All test results are publicly available.

In the wake of the spill, NOAA and the FDA developed a chemical test to detect the presence of dispersants in fish, oysters, crabs and shrimp.

The level of concern for dispersants is 100 parts per million for finfish and 500 parts per million for shrimp. The test can reliably detect Dioctyl sodium sulfosuccinate (DOSS) at levels of 2000 times below the lowest level of concern.

The results of chemical testing showed that 99 percent of samples contained no detectable dispersant residues, and the few samples that did contain dispersant residues showed levels more than 1000 times lower than FDA levels of concern.

No oil or sheen has been documented in the area that was reopened Tuesday since August 4. At its peak, the area of the Gulf that was closed to fishing was 88,522 square miles, or 37 percent of federal waters in the Gulf of Mexico.